Alternating-current induction-motor.



No. 763,379. PATENTBD JUNE 28, 1904. G. B. DUSINBBRRE.

ALTERNATING CURRENT INDUCTION MOTOR.

APPLICATION FILED DBO.Z9, 19oz. RENEWED we. s, 1903.

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PATENTED JUNE 28, 1904.

G. B. DUSINBERRE. ALTERNATING CURRENT INDUCTION MOTOR.

APPLICATION FILED DEG.29, 1902. RENEWED AUG-3.1903.

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WITNESSES:

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UNITED STATES Patented June 28, 1904.

PATENT GEORGE B. DUSINBERRE, OF EDGEIIOOD PARK, PENNSYLVANIA, ASSIGNOR TO WVESTINGHOUSE ELECTRIC & MANUFALTURING COMPANY, A CORPORATION OFPENNSYLVAVIA,

ALTERNATlNG-CURRENT INDUCTION-MOTOR.

SPECIFICATION forming part of Letters Patent No. 763,379, dated June 28, 1904.

Application filed December 29, 1902. Renewed August 8, 1903. Serial No. 168,765. No model.)

To all whom it may concern.-

Be it known that I, GEORGE B. DUSINBERRE, acitizen of the United States, residing at Edge- Wood Park, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Alternating-Ourrent Induction-Motors, of which the following is a specification.

My invention relates to electric motors of the induction type, in which the propelling energy is polyphase and is supplied to only one of the members in such manner as to produce a rotating field that sets up by induction a corresponding field in the other member of the motor, and thus produces mechanical rotation of that member which is susceptible of such motion.

The object of my invention is to provide a simple, compact, eflicient, and easily controlled means for introducing resistance into the circuit of'the secondary member of an induction-motor when such member constitutes the rotating part.

It has heretofore been the practice in many cases to include more or less external resistance in the circuits of the secondary members of induction motors in order to keep down excessive currents in starting and to cut out such resistance when the motors have reached normal operating speeds. In the case of motors having stationary secondary members the introduction and cutting out of suchresistance is a comparatively simple matter; but where the secondary member rotates the introduction and cutting out of the starting resistance is a more diiificult problem. My present invention is specially designed to both simplify and cheapen the construction of the resistance employed and also to so locate and arrange the resistance and the means for varying its active length that the parts shall be not only easily manipulated and controlled, but shall be so located as to be readily accessible and free from danger of interfering in any way with the operation of the main parts of the motor.

In the accompanying drawings, illustrating my invention, Figure 1 is a longitudinal sectional view of one end of the secondary member of an induction-motor and of my invention, the section of the latter beingon line I I of Fig. 2. Fig. 2 is a transverse sectional view on line II II of Fig. 1. Fig. 3 is a transverse sectional view on line III III of Fig. 1. Fig. 4C is a perspective view of the resistance element of my invention; and Fig. 5 is a diagram of the winding of the secondary member of the motor, the resistances connected thereto, and means for varying and cutting out such resistance.

The secondary member 1 of the motor comprises a suitable spider 2, a laminated slotted core 3, and a winding 4:, the coils of which are provided at suitable intervals with loads 5, which extend outward through the central bore 6 of the shaft 7 and laterally from said bore through openings 8 and 9. In the motor here indicated, three leads 5, corresponding to three phases of current, are employed. Six conductors 5 are employed for convenience merely, there being two of such conductors connected to the same point in the winding, so that they in efi ect constitute three leads. These leads 5 are connected by means of suitable terminal pieces 10 to binding-screws 11, mounted in and insulated from the head 12 of a cylinder 13, this cylinder being mounted upon and fastened to a sleeve 14, which is litted upon and keyed to the shaft 7. Fitted against but insulated from the head 12 of the cylinder by means of an annular strip 15, of insulation, are three ring-segments 1510f copper or other good conducting material, and at the other end of the cylinder is a ring 16, between which and the ring-segments 15 is clamped a laminated ring or cylinder 1'7, formed of interleaved helical strips of resistance materialsuch, for example, as iron. The ring-segments 15, the ring 16, and the resistance-coils 13 are clamped together and to the head 12 by means of bolts 18, which are insulated from the said rings and cylinder by insulating-tubes 19. The outer end of the cylinder 13 is closed by means of a cap 20, which is screwed or bolted to the ring 16, as indicated in Fig. 1.

The resistance-cylinder 17 is here shown as built up of overlapping segments of iron separated by suitable insulating-strips, such as mica, (see Fig. 4,) so as to form three interleaved helices 21, 22, and 23, the coils 22 and 23 being indicated in outline only in order that they may be distinguished from the coil 21, which is shown as comprising three layers of resistance-strips. The three coils are structurally and functionally alike, and each may be formed by bending one or more strips of sufficient length into an unbroken helix, if the physical characteristics of the metal permit, instead of building it up of comparatively small segments, as indicated. The inner ends of the three coils 21, 22, and 23 are respectively in contact with the corresponding ringsegments 15, as indicated diagrammatically in Fig. 5 of the drawings. In order to vary the amount of this resistance which is included in the several circuits of the secondary winding 1 of the motor, I provide a series of laminated-copper brushes 24:, (here indicated as six in number,) these being fastened, by means of screws 25,'to a ring 26, which surrounds and makes a sliding fit with the sleeve 14. The ring 26 is provided with a transverse bar 27, which projects through longitudinal slots 28 in the shaft 7 and the sleeve 14 and also through a transverse-slot in the head 29 of an adjusting-rod 30, in which slot the bar makes a sliding fit, the head 29 also making a close sliding fit in the bore 6 of the shaft. The outer end of the adjusting-rod 30 is provided with a 4 head 31, which is fastened upon the end of the shaft so as to have a free movement of rotation with reference thereto, but having no relative longitudinal movement, this arrangement being made in order that the brushes may be readily adjusted when the shaft is rotating.

It will be seen from the construction shown and described that when the brushes are at the outer end of the cylinder 13, the entire resistance will be in circuit and that as the brushes are moved inward the resistance will be gradually cut out of circuit until the brushes move into engagement with the inner surfaces of the ring-segments 15, when the resistance will be entirely out of circuit.

The details of construction are obviously susceptible of variation from what is shown without departing from the spirit and scope of my invention, and the resistance may be located elsewhere than on the end of the shaft, if desired.

I claim as my invention-- 1. In an induction-motor, the combination with the rotatable secondary member having a hollow shaft, of helical resistance-coils hav ing exposed inner surfaces and mounted upon said shaft, a contact member mounted within said coils and means for adjusting said memher to vary the active lengths of said resistance-coils.

2. In an induction-motor, the combination with the rotatable secondary member, of helical resistance-coils mounted upon the shaft of said member'and connected to the secondary winding, and a longitudinally-adjustable contact device located inside the resistance-coils and making contact with the exposed inner surfaces thereof.

3. In an induction-motor, the combination with the rotatable secondary member, of helical resistance-coils having exposed inner surfaces and mounted upon the motor-shaft, a contact device located inside said coils and means for adjusting said device along the shaft to vary the active lengths of the resistance-coils.

4. In an induction-motor, the combination with the rotatable secondary member, of interleaved helical resistance coils mounted upon the motor-shaft and connected to the secondary windings of the motor, contactbrushes mounted upon the shaft inside the resistance-coils and means for adjusting said brushes along the shaft to vary the active lengths of said coils.

- 5. In an induction-motor, the combination with the secondary member and its shaft, of interleaved, helical resistance-coils and a casing therefor rigidly attached to the motorshaft, contact-bru shes mounted upon the shaft within the coils and means for adjusting said brushes longitudinally upon the shaft to vary the active lengths of the coils.

6. In an induction-motor having a rotary secondary member provided with windings adapted to polyphase currents, the combination with said member and its shaft of a plurality of interleaved resistance-coils having exposed inner surfaces and rigidly mounted upon said shaft, a short-circuiting contact device and means for moving the same along said coils longitudinally of the shaft.

7. In an induction-motor, the combination with the rotatable secondary member, of helical resistance-coils having exposed edges and mounted to rotate with said secondary member, a contact member mounted to engage the exposed edges of said coils and means for adjusting said member to vary the amount of resistance in circuit.

8. In an induction-motor, the combination with the rotatable secondary member, of helical resistance-coils having exposed edges and mounted to rotate with said member and connected to the secondary winding, and an adjustable contact device making contact with the exposed edges of said resistance-coils.

9. In an induction-motor, the combination with the rotatable secondary member, of helical resistance-coils having exposed surfaces and mounted to rotate with said members, a contact device making contact with the exposed surfaces of said coils and means for adjusting said device to vary the amount of resistance in circuit.

10. In an induction-motor, the combination with the rotatable secondary member, of interleaved helical resistance-coils mounted to rotate with said member and connected to its windings, contact-brushes mounted to engage the exposed surfaces of the resistance-coils and means for adjusting said brushes to vary the amount of resistance in circuit.

11. In an induction-motor, the combination with the secondary member and its shaft, of helical resistance-coils having exposed edges and a casing therefor rigidly attached to the motor-shaft, contact-brushes mounted upon the shaft to engage said exposed edges and means for adjusting said brushes longitudinally upon the shaft to vary the active lengths of the coils.

GEO. B. DUSINBERRE.

Witnesses:

H. C. BEAVER, JAMEs B. YOUNG. 

